Oreo is a brand of sandwich cookie consisting of two wafers with a sweet creme filling. It was introduced by Nabisco on March 6, 1912, and through a series of corporate acquisitions, mergers and splits both Nabisco and the Oreo brand have been owned by Mondelez International since 2012. Oreo cookies are available in over one hundred countries. Many varieties of Oreo cookies have been produced, and limited-edition runs have become popular in the 21st century.
While Oreo is actually an imitation of the Hydrox chocolate cream-centered cookie, which was introduced in 1908, Oreos far outstripped Hydrox in popularity, so much that many think Hydrox is an imitation of Oreo, rather than the other way around. Oreo is the best-selling cookie brand in the United States and, as of 2014update, the best-selling cookie globally.